


Theoretical

by flootzavut



Category: NCIS
Genre: Alternate Universe, Episode Related, Episode: s03e08 Under Covers, F/M, Fake/Pretend Relationship, Kate Lives, Kibbs, Smut, WIP, episode rewrite, smut with plot
Language: English
Status: In-Progress
Published: 2017-03-13
Updated: 2017-06-03
Packaged: 2018-10-04 05:42:04
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 4,430
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10269503
Author URL: https://archiveofourown.org/users/flootzavut/pseuds/flootzavut
Summary: It may be undercover, it may all be for a case, but he's about to see Caitlin Todd naked.He must've done something exceptionally good in a past life.





	1. Chapter 1

**Author's Note:**

  * For [jenni3penny](https://archiveofourown.org/users/jenni3penny/gifts).



> Because I just found an old, old email where you flailed about the very first parts of this ;D
> 
> A Kibbs reimagining of Under Covers.
> 
> May be slow posting... please bear with me!

* * *

**_Theoretical_ **

* * *

 

He steps toward her slowly, trying not to get too caught up in the moment, trying not to get entirely distracted, but his heart is pounding like he just ran a marathon and it's extremely difficult to keep his focus.

"Whaddya think?"

She shrugs, as if it's barely adequate. "It seems fine."

He cocks an eyebrow and steps closer. There's a whole passel of emotions on her face - nerves, uncertainty, maybe even excitement. "Fine?" he teases. "What's wrong with it?"

Her smile edges up. "It's a room. It has a bed." She reaches out to take hold of his tie and tug him a little closer. "What more do we need?"

He swallows hard and leans down to ghost his lips over hers, then tangles his hand in the back of her hair and cradles her head as he lets the kiss deepen. When they surface, her eyes are closed and her mouth is open, and he takes a few seconds to savour her soft expression and the taste of her on his tongue before she looks up at him again.

"Guess you have a point." His voice is rough and dark. He wonders if she realises he's not having to fake it.

She reaches up to undo the tie at the back of her dress, her eyes wide, her teeth worrying at her lip, and Gibbs tries his damnedest to keep on breathing. It may be undercover, it may all be for a case, but he's about to see Caitlin Todd naked.

He must've done something exceptionally good in a past life.

Her fingers fumble with the dress. He leans in with feigned nonchalance. "Lemme help you with that." He undoes the bow, then raises an eyebrow down at her, asking the question. They can't afford for the answer to be no and they both know it, but still, he wants to give her the moment.

Hell, who's he kidding? He needs a moment himself.

She nods, and to his surprise there's suddenly a little grin on her face. He lets the dress slither down to pool at her feet and grins himself as he looks down at her. Can't exactly help it. There she is, dressed only in panties that perfectly match the silk round her ankles, and it's his sworn duty to his country to get her into the bed behind them and make her moan for more by any means necessary. He kinda hopes she'll require some assistance in the acting department.

Yeah, he thinks, as he leans in to kiss her again. Some days, he really loves his job.


	2. Chapter 2

_More work days like this'd be really nice._  'Nice' being the most ridiculous understatement he's made in his life.

Granted, simulating sex with your (young, beautiful) colleague has its moments of awkwardness, but he's almost naked and kissing an almost naked Kate, and that's the kind of awkward he can most definitely live with. He's strangely thankful for greying assassins who have a taste for younger wives and get themselves killed on the road.

He's gonna have to be careful he doesn't actually come all over her stomach from how fucking  _delicious_  it is to have her body under his, his erection rubbing against her through his boxers and the satin of her panties. It's taking all his willpower to resist temptation, to keep this vaguely professional (if that's even possible); he wants to beg to be allowed inside her. He knew she was gorgeous, always assumed she'd be even more so without her clothes on, but the reality is breathtaking.

Kate is kissing him back with surprising enthusiasm, and her hands aren't shy, running up and down his spine and grabbing at his shoulders, even tentatively squeezing his ass. When he draws back to catch his breath, though, he can see the apprehension on her face.

It isn't, he's fairly sure, because of him or even because they're pressed together so intimately (oh God, so much naked skin,  _so_  much naked Kate), but because of the watchers they know about and the others they suspect are watching. She's a private kind of person, and having sex - even fake sex, even just a distraction so their colleagues can slip under the radar - with a rather clinical audience observing them, hearing every noise, even seeing their bodies moving on an infrared scope or worse? It's not something she's finding easy.

He bends down to nip at her ear and so he can speak without being overheard. "At least try an' sound like you're enjoying it, Katie, huh?"

She laughs softly, like he'd hoped she would, a little of her tension dissipating, then lets out a 'mmmm'. It's a start, and she even sounds like she means it, but she's too quiet, too nervous still.

"Louder." He's in bed with Caitlin Todd, ordering her to moan louder; if it wasn't for the potentially fatal outcome if they're not convincing, he'd laugh at how surreal this is.

"Mmmm," she says again, and granted, he likes it, but he's not sure how convincing it'll sound to an onlooker. "God, Gibbs, I'm no good at this." She presses her mouth close to his ear, speaks fast and low and sounds apologetic. "I'm gonna blow our cover, I don't know what to do." They put this op together so quickly, he suspects she hadn't thought it through this far when she said she'd do it.

He catches her mouth with his and kisses her again, since she seems okay with it. Of all the things they've done so far, it's the one thing that's unmistakably made her relax and go with the flow. (He's trying not to read too much into that.) He does his best to figure this out, even as he kisses her; maybe it's because she's so gorgeously distracting, but there's really only one way he can think of to help.

"Wouldya like... a hand?" he murmurs when they come up for air.

She blinks. "What?"

He shrugs a shoulder. "Could help ya with the, uh... sound effects."

"How?"

"By making 'em... not be fake." He maintains the eye contact, wills her to understand and agree, because he's really not sure how to have an actual conversation where he outright offers to make her moan for real, never mind have it covertly.

It takes a few seconds, then her expression clears. She looks surprised but not shocked or offended. He waits as she processes the idea, her mouth opening and closing a few times like she's about to speak but can't quite get the words out.

"Okay," she says at last. She nods at him, suddenly sure, almost eager in fact, and he blesses every last deity he can think of. She's finding this hard, but she trusts him, and he gets to touch her.

This is officially the best day he's ever had on this job.

She worries at her lip with her teeth as he slides his hand down her body. He nudges them away with his own tongue, then sucks lightly. Her groan is louder and much more convincing this time; her fingers clutch at the back of his head, and she shivers in a way he's sure she couldn't fake.

"Good girl." He gently squeezes her breast. "Relax, I got ya." He leans down to speak softly in her ear again, so soft no one else will be any the wiser - no matter how close they're listening. "They think you're fakin' it, remember?" He knows instinctively it's the NCIS team she's so self-conscious about. "Don't need to be embarrassed. Just let go, enjoy."

There's a pause, then she nods again, and this time when he tugs on her nipple and bites the side of her neck, the sound she lets out makes his entire body clench.

"Good girl," he says again. His voice is low and gravelly, he can't help it. He wonders if she has he slightest idea how amazing she looks and sounds and feels, how relentlessly enticing she is. He nuzzles into the tender skin of her throat, and to his delight she arches into his touch. "That's it. I got you, all right?"

She answers him with a wriggle and a whimper as he strokes her stomach with the back of his hand. Her skin is warm and velvet soft, and she is... "Glorious," he says aloud, then shakes his head.

He supposes it's not too hard to believe it's something a happily married man might say about his wife, if she was as beautiful as Kate, so at least he has an excuse. But if Kate registered what he said, remembers it later, he's pretty sure she knows him well enough to figure out from his tone of voice that he wasn't just playing a part.

Too late to worry about that now, though.  _Might as well go for broke_.

Feeling daring, he leans down and takes one of her nipples between his lips, hoping he's not pushing his luck, then chuckles into her skin when her fingers tighten in his hair, demanding he stay there as she lets out more sounds of enjoyment. He stops worrying about keeping them covered up, lets the comforter slide down his shoulders. He can preserve Kate's modesty against the possibility of video surveillance with his body well enough, and God help him, he wants to see.

Her breasts are truly magnificent, full and pert, and sensitive as hell given her reaction. They're everything he wants in his hands and mouth, and he could do this more or less forever. He sucks, licks, grazes his teeth over her, laughs when her feet scrabble at the bedclothes and she whines. This might well be madness, but it's definitely working.

He can sense her sinking into it, her fears and concerns and self-consciousness melting slowly away under his touch and his mouth. He's always thought and hoped he could make her feel good. He can't quite believe he's getting the chance to prove it.

"That's it. Just relax."

His hand slips between her legs and into her panties, into her damp curls, and he's gratified by the moisture coating his fingers even before he slides a finger further in and over her clit. He didn't dare expect her to be this wet, this genuinely and unmistakably turned on, and it's incredibly hot.

She rocks against his touch, getting lost in the moment. "Yes. God, yes." He will treasure these moments forever: the sound of her pleasure, the flush of arousal spreading across her chest, the way she feels under his hands and mouth. 'Glorious' was exactly the right word.

He lets her set the pace, follows her avidly, watching with something akin to delight as she gets off against his fingers. He alternates between licking and nibbling her breasts and just looking at her, marvelling at her beauty and her surrender. "You are..."

Her movements become gradually harder and wilder, and she gasps, demands more in a shaky voice. He's thrilled to oblige, his fingers making dancing, teasing circles through her slick, silken folds.

With his free hand, he tugs at her underwear. Modesty is the least of her concerns now she's grinding wantonly against his hand, and he doesn't need anything getting in the way as he pleasures her... and, admittedly, he still just kinda wants to get her completely naked.

She doesn't protest, even helps him ease them over her hips, and when they're gone she spreads her legs wider and pushes up into his touch. On the whole, he's pretty sure she's okay with this. And the view is most definitely worth it.

He lets himself stare down at her, trying to take everything in, impress it permanently into his memory. Her strong, slender body moving against his fingers, her mouth open and gasping, her breasts heaving with each breath and her nipples teased into hard points by his tongue. The way she's spread out under him like a banquet. All things he never thought he'd get to see, and he can hardly believe he's seeing them now.

He leans down and kisses her again, swallowing her moans, momentarily letting himself ignore that this is a ruse for someone else's benefit.

Even so, he can't entirely forget they're here for a reason, that their lives (and possibly the lives of others) might depend on this seeming real.

They definitely need a grand finale if they're gonna make it convincing, and she's a lot more relaxed and an awful lot noisier now, but he's still not sure she's ready to scream like she just came her head off, which could be a problem.

It takes a moment, but then the solution occurs to him with a smile against her lips and he almost wants to laugh. The simplest way to make Kate having an orgasm sound authentic? Actually make her come. And hey, it sure sounds like an enjoyable challenge.

He can't figure out how to ask permission to try, so he goes for the next best option. His fingers slip inside her (and dear Lord, he still can't quite wrap his mind around it - how,  _how_  is she so wet?) and he lets his thumb slide teasingly over her clit. He moves away from her mouth so the sound effects for their audience are loud and clear, kissing along her jaw then licking the top of her neck. "Okay?" he breathes in her ear.

"Oh, God," she murmurs, then lets out a throaty moan he's sure will satisfy whatever audience they have. It's definitely satisfying him. He's gonna be dreaming about it forever.

"I'll take that as a yes."

She nods violently. "Please."

Chuckling again, in amused disbelief, he starts to fuck her with his fingers, his thumb now directly circling her clit. She throws her head back and keens, and he finds himself wondering if she'll let him do this again, except with his mouth between her legs. He cocks his fingers inside her with each stroke, her gasp reassuring him he's most definitely found her sweet spot. She ripples under him, letting out the unmistakable cries of a woman nearing completion and desperate for an orgasm.

"Good girl." He whispers it, for her ears only. "Just let go for me, Katie. Come for me."

She wails, then she's shaking and cursing, and coming so hard around his fingers he involuntarily imagines what it would be like if his cock was inside her instead, and moans himself as he watches her fall apart.

When she comes down from her high they're both breathing hard, and Gibbs can't stop himself grinning as he rolls over to flop down beside her, tugging the bedclothes over her just in case. If he could leave her naked and just look at her for hours he would, but they don't know if there's anyone watching, and she'd never forgive him for exposing her to someone else, even if she doesn't seem to mind his perusal.

She looks at him, wide-eyed and mind blown, and while he'd prefer to be somewhere private with her, somewhere he could safely make her scream his name and he wouldn't be left hard as stone and in desperate need of excusing himself for a long, hot shower with a lot of soap, he feels pretty damn good about himself right now. He sucks his fingers into his mouth and doesn't miss the way her eyes darken as he slowly licks the flavour of her off of his skin, savouring the moment. Oh, how he'd love to taste her properly. Even secondhand, she's delicious.

She shakes her head. "Wow."

"Yeah, that's what they all tell me."

He can't help himself, but it's amply repaid when Kate giggles breathily and slaps his chest with the back of her hand, diffusing the awkwardness of the moment.

"Incorrigible."

He shrugs. "Guilty as charged." He cocks an eyebrow and moves in closer again to speak to her alone. "Think we convinced 'em?"

Her cheeks are already flushed from her orgasm, but somehow she still contrives to get redder. To his surprise, though, she also leans into him, intimate and comfortable, nuzzles against his mouth. "Sure convinced me," she admits.

She sounds sated and sleepy, and her eyes are half closed. He grins and kisses her cheek, then gives in to stupidity, propping himself up on one elbow so he can kiss her mouth with all the tenderness and passion he most definitely shouldn't allow himself to feel.

"Gonna go grab a shower," he murmurs when they resurface, biting back the urge to ask if she'd like to join him - if she'd like to help him out.

He's hoping she's put his erection down to the natural male reaction to kissing and touching a naked woman, rather than the painfully sharp attraction he has to this particular woman regardless of whether or not she's clothed. In the circumstances, asking for her help jerking off isn't really wise or even feasible.

Unfortunately.

She smiles, blinks slowly, and with a sigh he pushes up from the bed and forces himself to walk away before temptation can get the better of him.

He makes it all the way to the door of the ensuite before he gives in and glances back. He's trying not to show her the state she's left his body in, but he can't resist looking over his shoulder. When he discovers she's watching him, looking at him, at his ass, almost covetously, he can't help his grin. He has to force himself to turn away.

Once safely shut in the bathroom he takes a deep breath and shakes his head, grinning like an idiot. Maybe he should be having a cold shower instead. Or possibly an ice bath.

He's not complaining, though. He needs to make sure he doesn't get distracted from the actual case, and this situation might completely finish him off both mentally and physically, but making Kate come all over his hand and calling it work?

"Best damn assignment ever."


	3. Chapter 3

Kate lets herself float, not even attempting to think anything more coherent than 'Wow'. She's so relaxed, so thoroughly blissed out. The knowledge several people just witnessed her coming apart should by rights be at the forefront of her brain, and horrify her. Maybe she'll be horrified later, but right now she's having trouble getting beyond the feeling of satisfaction.

She has no idea if they've convinced their onlookers they're a legitimate couple enjoying one another after a long flight; all she knows for sure is that it really worked for her. She's known for a long time that Gibbs is a dangerous kind of guy, in lots of ways, but what he can do with two fingers and a thumb probably shouldn't be legal.

Or maybe it was the way he looked at her, the way he watched her, his eyes dark, his voice low and rough in her ear. His intense focus. It's no surprise to her he's as intense in bed as he is at work, and sure, she'd had a good idea that pretending to be a married couple would be... interesting. But she hadn't banked on her reaction, didn't think about what potentially being under such intense surveillance might require. And even if she'd thought far enough ahead to imagine them faking sex, she could never have predicted Gibbs would end up actually getting her off instead of pretending, never mind being prepared for how careful and thorough and - she can't think of a better word - loving he'd be as he did it.

If this is Gibbs faking it...

It surprised her and disarmed her, and letting him take her to pieces so thoroughly has left her wondering how exactly she's going to deal with, potentially, a whole weekend of this. They're hardly gonna spend the whole weekend in bed - they're supposed to be assassins, after all, not newlyweds - but she feels like just sharing a bed with him is gonna seriously mess with her head.

Gibbs is, admittedly, a good-looking guy, with enough good and interesting qualities to (mostly) make up for the times he's a total bastard, but until now she's always managed to treat his attractiveness as a theoretical thing - something she notices but which doesn't affect her, just another quality to add to the profile.

Suddenly, theory has given way to practice, and she wasn't even close to being ready for it.

There are lots of things she isn't about to forget, even if she tries very hard indeed. What's worse is she's not sure she wants to forget, because it was so unexpectedly... good. Tender. The way he gave her a second before her dress dropped to the floor. The way he looked at her, eyes dark and soft, like he'd been looking forward to this forever. The way he kissed her, careful but decidedly passionate. His disbelief and enjoyment as he made her come.

His body, firm and strong. Not young, and decidedly worn, but she's had young and smooth and perfect, and she finds it... overrated. Grizzled and scarred but also experienced and confident and so, so thorough? It's new and different and so far, she really likes it.

She imagines what it might be like if this was for real. If they didn't have to think about spectators. If instead of trying to figure out how best to fool their eavesdroppers, all they had to think about was giving and receiving pleasure. She has a strong suspicion she'd never want to stop. She can't quit thinking about it, can't let go of this particular bone, even though she knows she really should.

Her mind is patching together all the half formed thoughts she's had over the past few years, every foolish 'I wonder', every time she's ever had an inappropriate fantasy, every moment when she's let her mind wander and it wandered to Gibbs. She's had plenty of those moments, and she always took great pains to squash them, but she can't seem to stop herself now. Can't stop imagining what it would be like to feel him enter her, his body pinning her to the bed, her fingernails digging into her skin as he filled her up. She pictures herself climbing on top of him and slowly, slowly sliding down, inch by inch, impaling herself on him as he begs her not to be a tease. Sitting on his face and grinding down, or just melting back into the bedclothes with his mouth between her legs. She wants so many things, and she can't drag her thoughts out of the gutter and back to some kind of professionalism.

She remembers the erection he couldn't hide, moving against her panties and her thigh. The erection she's pretty sure he's taking care of right now. She wonders if he's thinking of her as he does so.

It's too bad she isn't braver, more brazen. Maybe he'd like a little help... she's surprised, borderline appalled with herself, but she'd really like to join him in there, drop to her knees in front of him, take him in her mouth, lick and suck until he can't stand up. She doesn't even think he'd object, and it's such a tempting image. She knew he was packing heat, she's not blind, but it's different when she's felt it up close and personal; now she'd really like to see, to touch. But even though her body is still shivering with pleasure, she can't quite bring herself to proposition her boss with no excuse, not even a slender one. Never mind do so in a hotel suite wired into MTAC and with God knows who else listening in.

She reminds herself reluctantly that they have a job to do, and that - much as her imagination wants to pretend otherwise - this isn't her and Gibbs enjoying a dirty weekend.

With an effort, she levers herself upright, swings her legs so she's sitting on the edge of the bed, then stands up, a sheet draped around her for modesty, just in case. Her knees are wobbly from her orgasm, but she forces herself to gather her dress and panties from the floor, hanging the dress in the closet (and trying to ignore just how wet she got her underwear before Gibbs disposed of them), wrapping herself in the white, fluffy robe she finds folded on one of the chairs.

No longer entirely naked, she feels less exposed to whoever is listening (or worse, watching), and can breathe a little easier. She's still moving like her body isn't quite awake, slow and dreamy; she has no real idea how long she's needed her to gather herself together, but she's taken by surprise when Gibbs emerges from the ensuite.

He's also in a bathrobe, barefoot, his hair damp and messy from the shower, smiling as he crosses the room to stand in front of her, and she gulps up at him. She remembers admiring - okay, ogling - the back view as he left her on the bed, and she assumes he's lost his boxers now, and it takes all her willpower not to undo the robe and slide her hands inside and over his naked skin.

(She can't do anything about the way heat rushes to her cheeks.)

He leans down to press a brief, chaste kiss to her lips, and they grin at one another foolishly. She really has no idea where the boundary lies between the case and the impossible to dismiss reality of his voice and his touch. Could he really have touched and loved her so tenderly just for show? Could the way he's gazing down at her now, his expression soft and warm, just be part of their cover? She doesn't know.

"Alors, ma chérie."

His voice is as soft and warm as his face, and Kate swallows hard. Gibbs murmuring sweet nothings to her in French is another aspect of this case she never could've expected and has no clue at all how to deal with.

They stare at one another for an age, or that's how it feels. Kate has so many things she wants to ask or say, and not a single one of them seems appropriate or acceptable in this situation. The silence stretches out; he's looking at her with unabashed curiosity, his eyes taking in her whole face then returning to stare into hers. Eventually, he takes a breath, and Kate is caught between relief that he's going to break this pregnant silence, and wary anticipation of what he will actually say.

**Notes for the Chapter:**

> Alors, ma chérie = So, my dear


End file.
